Hello all..
Kinda stuck here, if I didnt shave my head I am sure I would have pulled my hair out by now..
I have a 2000 ml320, 178k miles...
The other day car was sputtering pretty bad... I had driven it all day without problems, then after parking and 20 minutes later I got into it to run to the store and thats when it was all sputtery..
For the hell of it I hooked up the scanner and got p0400... EGR valve... After getting some great advice from here, I pulled off the tube and it was clogged pretty bad, so I cleaned it using the "rotor rooter" gimmick I read on here.. After doing so.. same problem, so I got a new EGR valve... replaced it and still running like crap... After leaving it run for about 1 hour, I scanned it again and got p0110... Intake Air temp... leading to the MAF... Seeing as I just replaced it in June of last year I didnt think it would be that, (with a cheap one from ebay, dont get them) I ordered a bosch from autohausaz yesterday and got i this afternoon... Threw it in and it was still running crappy... Let it run for a bit, scanned it and p0110 again..... Luckily for me I also have a 98e320, which shares the same engine, therefore alot of the same parts.. I pulled codes on it, got nothing, then swapped MAF's... the e class is running like a champ.... the ml on the otherhand.. well, it did run better.. I drove around for about 25 miles, much better, but it was bogging down everynow and then... Checked for codes and got a pending p0170 and p0173, no CEL, possibly didnt drive enough...
So, theres my long winded explanation of whats going on... What else could it be... Im at my wits end...
Thanks in advance...
Randy

Well, I ket at it and couldnt find anything... checked for vacuum leaks, best I could, even disconnected the MAF to see if anything would change, and it did, drastically worse... The onl thing I can think of is the fuel pump... I already changed the filter, to the "new one" back in June of 09.... The fuel pump is all I can think of... I even swapped the fel pump relay, which was pretty wam, compared to the others, with the horn relay (same relay) and it didnt do anything different....
I'm stuck.... Someone, please help......

OK folks, heres an update...
First off... 2000 ML320, 178k miles...
I started over and checked all of the stuff I pulled apart to look for a vacuum leak.. Although I didnt find one, I musy have had one, because it ran much better... Went out and ran the hell out it.. I was feeling pretty confident so I went out on the freeway.. getting on was just fine... I turned around at the next exit and when getting on the freeway then... Oh man... problem.. I was going uphill, therefore more power was needed.. Got around 3500rpms or so and it started bogging down, as if it was starved for fuel... When getting down below 3500rpms, all was fine.......
After getting home I checked for codes and got the dreaded p0170 and p0173.. I know that its not the MAF because I pulled it out of my 98 E320, and I did check for codes before I swapped them.. I drove the E class all day and no problems there, so I know its not the MAF.....
SO??? again, I am stuck.. Maybe check fuel pressure? What else could it be?

Went and got a fuel pressure gauge to see what was up with the fuel pressure and rule that out, or whatever...
key on, engine off.....About 30..... key on, engine on, about 50....
After the engine kicked down after the cold start, the pressure dropped to about 30....Then I wanted to see what would happen while i was revving the engine.... The pressure slowly made its way down to around 10, no hesitation or anything.....
After that I shut it off...
What do you think?

Now that you mention it, yes, the fuel pressure regulator is part of the fuel filter. Maybe I was leaning toward a fuel pump since I just had one go out on another car (1994 Plymouth Acclaim, 166,000 miles). But you said you replaced the filter and switched the pump relay recently and thought yourself that it might be the pump. Mine acted up on and off for about a month before I had it replaced.

fuel pump huh? What about fuel filter? Isn't the fuel pressure regulator attached to that?
in regards to normal fuel pressure... Not sure, as I just got the tester last night..

Fuel pumps are a known issue with the 163. Sounds like you're ready for one, just avoid flea-bay.

FWIW, the 163 forum has some great technical guys in there, so you're better off posting in your vehicle's native forum. Not that we want to get rid of you, but there are enough differences it can get confusing, particularly for others who come along later.

Socialism is a philosophy of failure, the creed of ignorance, and the gospel of envy; its inherent virtue is the equal sharing of misery. (Winston Churchill)

Thanks for the rplies guys..... The filter was replacedin June of last year and I swapped relays with the horn relay which is the same....
Im not worried about the job as I did all the other myself before, new filter and lines... Removing the seat wasnt that bad actually.....
I will check the w163 forum.. Thanks again guys....